1. Field of the Invention
The present invention relates to a thin film magnetic head having at least an inductive-type magnetic transducer for writing and a method of manufacturing the same.
2. Description of the Related Art
Improvements in the performance of a thin film magnetic head is sought since a surface recording density of a hard disk device has been improved. A composite thin film magnetic head having a structure, in which a recording head having an inductive-type magnetic transducer for writing and a reproducing head having a magneto resistive (hereinafter referred to as MR) element for reading are stacked, is widely used as the thin film magnetic head. The MR element includes an anisotropic magneto resistive (hereinafter referred to as AMR) element using an AMR effect and a giant magneto resistive (hereinafter referred to as GMR) element using a GMR effect. The reproducing head using the AMR element is called an AMR head or simply an MR head, and the reproducing head using the GMR element is called a GMR head. The AMR head is used as a reproducing head whose surface recording density is over 1 gigabit per square inch, and the GMR head is used as the reproducing head whose surface recording density is over 3 gigabit per square inch.
The AMR head has an AMR film having the AMR effect. The GMR head has a structure identical to the AMR head except that a GMR film having the GMR effect is used in place of the AMR film. However, when the same external magnetic field is applied, the GMR film exhibits greater change in resistance than the AMR film. As a result, the GMR head can increase the reproduction output three to five times the AMR head.
A method in which the AMR film being used as the MR film is exchanged with a material with better magneto resistive reaction such as the GMR film, and a method in which a pattern width of the MR film, especially the MR height, is made appropriate are used as the methods of improving the performance of the reproducing head. The MR height is a distance (height) between an edge of the MR element on the air bearing surface side to an edge thereof on the other side, and it is controlled by an etching amount of the air bearing surface. The air bearing surface, here, is a surface of the thin film magnetic head facing a magnetic recording medium, and is called a track surface as well.
On the other hand, performance improvements in a recording head have been desired while performance in a reproducing head has improved. A factor that determines the performance of the recording head is a throat height (TH). The throat height is a length (height) of a pole between the air bearing surface and an edge of an insulating film which electrically isolates a thin film coil for generating magnetic flux. A reduction in the throat height is desired in order to improve the recording head performance. The throat height is also controlled by an etching amount of the air bearing surface.
To improve a recording density among a variety of factors that influence the performance of the recording head, a track density of the magnetic recording medium must be increased. In order to achieve such an increase, a recording head with a narrow track structure must be realized in which widths of the top and bottom poles on the air bearing surface, which are formed on top and bottom sandwiching a write gap, are reduced from some microns to sub-microns. Semiconductor process techniques are employed to achieve the narrow track structure.
A composite thin film magnetic head having the above-described recording head and reproducing head is formed through a plurality of manufacturing steps, such as sputtering, photolithography, electrolytic plating, etching, polishing, and the like.
A problem associated with a series of steps of manufacturing a thin film magnetic head including a variety of steps as mentioned above is a long lead-time required to manufacture the head. Therefore, specific improvement measures, such as reduction in number of manufacturing steps, are desired for achieving a decrease in lead-time for mass production.
The present invention has been conceived in view of the above-described problems, and an object thereof is to provide a thin film magnetic head and a method of manufacturing the same that enable achievement of high-performance head characteristics without complicating the manufacturing steps.
The present invention provides a method of manufacturing a thin film magnetic head including two magnetic layers magnetically coupled to each other and having two magnetic poles which face each other with a gap layer in between and are to be faced with a recording medium, a thin film coil provided between the two magnetic layers with an insulating layer disposed in between, one of the two magnetic layers including a first magnetic layer portion which extends from a recording-medium-facing surface facing the recording medium in a direction away from the recording-medium-facing surface and has a constant width portion defining a track width, and a second magnetic layer portion covering an area where the thin film coil is disposed and partially overlapping, and magnetically coupled to, the first magnetic layer portion. The method includes a first step of forming a first insulating layer portion constituting part of the insulating layer and defining an edge of the insulating layer closest to the recording-medium-facing surface, and simultaneously forming a second insulating layer portion constituting part of the insulating layer in a region located farther from the recording-medium-facing surface than a region where the first insulating layer portion is disposed; a second step of forming the first magnetic layer portion; a third step of forming a first thin film coil pattern constituting part of the thin film coil, and simultaneously forming a connection pattern integrally with the first thin film coil pattern on the second insulating layer portion; a fourth step of forming a third insulating layer portion constituting part of the insulating layer so as to cover at least the first magnetic layer portion, the first thin film coil pattern, the second insulating layer portion, and the connection pattern; a fifth step of polishing and planarizing a surface of the third insulating layer portion until at least both of the first magnetic layer portion and the connection pattern are exposed; and a sixth step of forming a conductive layer pattern to be electrically connected to the exposed portion of the connection pattern.
In the method of manufacturing a thin film magnetic head of the invention, the connection pattern formed integrally with the first thin film coil pattern is disposed on the second insulating layer portion formed by the same step as the step of forming the first insulating layer portion. As a result, an upper surface of the connection pattern is positioned higher than that of the first thin film coil pattern. Therefore, when, after burying the first thin film coil pattern and the connection pattern with the third insulating layer portion, a surface of the third insulating layer portion is polished until the first magnetic layer portion and the connection pattern are both exposed, only the connection pattern is exposed while the first thin film coil pattern remains unexposed. As the second insulating layer portion is formed by the same step as the step of forming the first insulating layer portion, no additional steps are required for forming the second insulating layer portion.
The present invention provides a thin film magnetic head including two magnetic layers magnetically coupled to each other and having two magnetic poles which face each other with a gap layer in between and are to be faced with a recording medium, a thin film coil provided between the two magnetic layers with an insulating layer disposed in between, one of the two magnetic layers including a first magnetic layer portion which extends from a recording-medium-facing surface facing the recording medium in a direction away from the recording-medium-facing surface and has a constant width portion defining a track width, and a second magnetic layer portion covering an area where the thin film coil is disposed and partially overlapping, and magnetically coupled to, the first magnetic layer portion. The insulating layer includes a first insulating layer portion defining an edge of the insulating layer located closest to the recording-medium-facing surface, a second insulating layer portion disposed in a region farther from the recording-medium-facing surface than a region where the first insulating layer portion is disposed, and a third insulating layer portion filled up to a surface flush with an top surface of the first magnetic layer portion. The thin film coil includes a first thin film coil pattern, and a connection pattern disposed on the second insulating layer portion and formed integrally with the first thin film coil pattern. Part of a predetermined conductive layer pattern is disposed on the connection pattern.
In the thin film magnetic head or the method of manufacturing the same of the invention, the conductive layer pattern may be a wiring pattern for supplying electricity to the first thin film coil pattern. In such a case, the conductive pattern is preferably formed of the same material by the same step as the second magnetic layer portion.
Further, in the thin film magnetic head or the method of manufacturing the same of the invention, when the thin film coil further includes a second thin film coil pattern, the conductive layer pattern may be provided as the second thin film coil pattern. In such a case, a fourth insulating layer portion constituting part of the insulating layer may be provided to bury the conductive layer pattern.
Other and further objects, features and advantages of the invention will appear more fully from the following description.